When an elevator is to be installed in a building, the delivery limit for the elevator supplier on each floor is generally the door opening provided for a door in the landing wall. As the case may be, the door opening is somewhat larger than the space required by the frame of the landing door. The gap remaining between the frame and the wall structure has to be covered not only because of esthetic and safety considerations but also to comply with the fire safety regulations of many countries. The door and the structure joining it to the door opening must withstand for example heat of 1000.degree. C. for two hours. On the other hand, the operating environment may require structures as light and inconspicuous as possible. For example, in an elevator shaft with glass walls, the aim is to maximize the transparent wall area.
In elevator technology, there were previously known solutions in which a vertical steel plate is attached to the vertical part of the frame of the landing door of the elevator, on the side facing the shaft. The plate is also attached to the wall structure. Alternatively, the other edge of the plate is not attached to the wall but the gap between the plate and the wall was sealed with insulating material. In another previously known solution, the gap between the frame and the wall was simply filled with insulating material in cases where tight mounting tolerances have been achieved.
The problem in previously known technology is that the manufacturing tolerances may vary considerably, which means that plates of several widths must be available. In case of fire, the structures undergo deformations causing changes in the gap between the frame and the door opening. Especially if materials deformable in fire situations are used, a gap providing passage for flames between the shaft and the landing will be formed, particularly when the insulating material is completely loosened. In scenic elevators, the supporting structures and therefore also the supports surrounding the door opening as well as the frame placed in the opening are made as light and small as possible. Solving the problems with previously known technics requires extra work and materials, increasing the costs.